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11

The term "Arduino compatible" basically means nothing. Many sellers use the term more as marketing ("You can make this work with your Arduino!") than anything else. The Arduino is (usually) just an ATMega microcontroller on a board, that ATMega is very similar to many other microcontrollers. Nearly all of them work with a supply between 2 V and 5 V as does ...


6

This might not be the only issue, but is almost certainly is one of them: the LM317 cannot supply 2A (its output transistor simply cannot pass that much current). But even if it could, it probably would go into thermal shutdown. It is a linear regulator and linear regulators work by turning excess voltage to heat. That means the higher your input voltage is ...


5

The fears are unfounded - both technologies are fundamentally safe. The only conceivable damage from radio waves is heating of biological tissue and and Specific Absorption Rate (SAR) testing is specifically designed to ensure no harmful exposure levels to humans in nearby usage and Maximum Permissible Exposure (MPE) at distances past 20cm. "In the United ...


4

Manufacturers of lithium thionyl chloride battery packs use hybrid layer capacitors (HLCs) for this exact purpose. For example see Tadiran.


4

Supply transient problems in GSM radios are common. My recommendation is to beef up the traces carrying high current by soldering wires on the surface of the PCB parallel to the traces. Another option is to scratch the solder mask off and add a thick layer of solder on top of the traces. It's also possible that the problem is in your external power supply. ...


3

This evidences how each one of us sees the internet from his point of view. Starting by some basics have a look at this picture: Image Attribution : Chunte7 [CC BY-SA 3.0 (full license)] As you can see the internet can be divided into 4 layers, some times 5 by dividing the network access layer into other two layers, that are in the image on the right. ...


3

It depends a little bit on what you're implementing but as mentioned in the comments as tasks usually handle/emit reocurring events they all should contain an infinit loop so this is not a don't. What you should keep in mind when introducing multiple tasks is the required processing time and the fact that a context switch requires resources and processing ...


2

As Andrew Morton has mentioned it is a loading coil. Mainly used for impedance matching. I found some calculations in the following article. Loaded Quarter Wave Antenna Inductance Calculator


2

Use AT+CIPGSMLOC command. It works well in SIMCOM modules. This command needs the GPRS service attached before you use it. So first attach the GPRS service using appropriate command sequence then use this command to get date and time from GSM network. For attaching GPRS service: CMD:AT+CGATT=1 CMD:AT+SAPBR=3,1,"Contype","GPRS" CMD:AT+SAPBR=3,1,"APN","" ...


2

This 4 band and Class 12 Modem chip is capable of supporting low bandwidth applications up to 85.6kbps up and down stream. Packets are kept small to reduce retry sizes when not received. Signal to Noise Ratio must increase above some threshold to achieve error free communication at fastest rates. This is often when the RSSI starts > -80dBm with a -105 dBm ...


2

(x)G is actually pretty meaningless. Since multiple technologies get called 3G and 4G, even though they are completely different and achieve different data rates. For example 3G speeds range from 144Kbps to 21.6Mbps. The providers of the 144Kbps network still call it 3G though. It doesn't really have anything to do with a service level. If your signal is ...


2

"Active antennas" include an amplifier to improve reception. This works well with things that only receive. GPS receivers and television receivers only receive. It is fairly easy to include an amplifier to make reception better. GSM has to transmit as well as receive. It is much more difficult to make an active antenna if you have to be able to transmit ...


2

It will be certainly compatible with any microcontroller. The keyword "Arduino compatible" generally means that some of the following are true (from most to least likely): Module likely uses 5V signaling, or is at least 5V tolerant It likely interfaces using one of the hardware interfaces available on Arduino (serial, I2C, or SPI) There may be an Arduino ...


2

When it say it is compatible with something you know that it will work with specific platform (if seller doesn't lie). To check if it will work with your specific platform you can check if specification are compatible with your platform. For modules you usually check power supply range, interface type and interface voltage. In your specific case these are: ...


2

Theoretically, you can design a multi-band antenna and use it for both GSM and 433MHz receiver. To combine the two radios to the same antenna you would need a diplexer, which could be implemented using a low-pass filter feeding the 433MHz receiver and a high-pass filter feeding the GSM radio. However, if you have enough space, I strongly recommend that you ...


2

The MQTT protocol sits on top of a long-lived TCP/IP connection. There is next to no chance that a cellular modem would maintain a TCP/IP connection while in sleep mode. So you won't wake up from a subscription firing. It's not impossible that once you wake up for some other reason and reconnect, depending on the configuration of the MQTT broker, that you ...


1

100uF capacitor consumes lots of inrush current at its start-up and I don't think LM317 can support with those short traces. Secondly, LM317 is an very good linear regulator with tight voltage regulation at its output and so you can move those huge capacitors to its input side and keep low capacitance (~10-20uF) at its output side. Irrespective of it, you ...


1

This is probably not the answer you are looking for, but those 2 boards are not the same. There are many different versions of the SIM800c breakout boards, and that means you cannot say for sure whether pinouts are the same with these 2. This bit of the answer you may enjoy less, although it is good news in that you can figure it out for yourself! You can ...


1

Thanks for reopening the question. This is not something that you would encounter on a regular basis but I've faced this same question several times over the past 10 years. Especially when you place GSM equipment on a high site (mountain) where there are two or more, non-synchronised GSM cell's visible. This will result in incorrect cell hand-over and ...


1

Is my analysis of the source of this EMC problem correct? (SMPS generating input noise due to high load). I don't know if this is the cause of your 'loud GSM buzz' but it is above the compliance limit, and your tests indicate that it is coming from the SMPS. The peak conducted noise at 150kHz is ~90dBμV or ~30mV, which is about what I would expect from ...


1

So after watching my terminal for hours I realized something interesting!sometimes When ping request is sent to gsm module without any delay I get frame error and noise error. In reference manual I understood that frame error occurs when mcu couldn't find stop bit and noise error occurs when sampling bits don't strongly prove 1 or zero (maybe I'm not ...


1

HTTP data is transmitted over TCP. Fundamentally when using "raw" TCP you will have to write some sort of system for framing messages, deciding their boundaries, handling transmission and server errors. HTTP gives you a standard way of doing that, but there are a lot of other standard protocols that you could use as well. Using HTTP will mean more software ...


1

Yes you can. Usually the cellular modules support both TCP and HTTP, so you can send any data you want. The connections are usually initiated and controlled via special AT commands over the UART.


1

Replace the fet for an MIC94064 or other smart high side switch. That's just very easy for starters. Little detail often omitted is that you have to put the pins of the atmega in high-z when you turn off the SIM868. Otherwise you might power the module via your IO pins. Add decoupling, at least 100nF and 1uF after the switch, near the pins of the SIM8686. ...


1

The output capacitance of the AMS1117 is too less, causing the 3V3 to be unstable. The datasheet recommends 22μF: The circuit design used in the AMS1117 series requires the use of an output capacitor as part of the device frequency compensation. The addition of 22μF solid tantalum on the output will ensure stability for all operating conditions. When ...


1

This is the power supply schematic provided in the datasheet, SIM800C-DS_Hardware_Design_V1.00, to which you refer. See section 4.1 So, yes, it would appear that your drawn schematic is correct. From section 4.1.1 Pin34 and Pin35 are VBAT input, Pin36 and Pin37 are GND of power supply, and VRTC pin is power supply of the RTC circuit in the module. ...


1

first send this two command AT+CLTS=1;&W AT+CFUN=1,1 and than AT+CLTS? check whether you get this reply +clts: 1 and than send this command AT+CCLK?


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